The proliferation of digital media on the Internet has exploded in recent years. With the increase of video and image creation along with its display, growth of theft and unauthorized redistribution of media across the Web has occurred. In general, producers of media intended to be viewed through the internet have an interest in protecting this content.
The advent of personal computers as household appliances has made it convenient for consumers to convert media (which may or may not be copyrighted) which is originally in a physical/analog form or a broadcast form into a universal, digital form (a.k.a. ripping) for location and/or time shifting purposes. Combining ripping with popular file and internet sharing tools has made unauthorized distribution of copies of copyrighted digital media much easier.
Digital rights management (DRM) is one method for protecting digital media. DRM refers to access control technologies used by publishers and copyright holders to limit usage of digital media or devices. DRM technologies attempt to control use of digital media by preventing access, copying, or conversion by end users to other media formats. It may also refer to restrictions associated with specific instances of digital works or devices. In practice, all widely-used DRM systems have been defeated or circumvented when deployed to enough customers. Restricting copying of audio and visual material is especially difficult due to the existence of the analog hole, and that are even suggestions that effective DRM is logically impossible for this reason. DRM can be expensive, intricate, and can complicate the viewing for some users.
Another media protection is through a watermark. Watermarking involves applying a recognizable image or pattern to a media, the image or pattern appearing lighter when viewed by transmitted light (or darker when viewed by reflected light, atop a dark background). Digital watermarking involves embedding information into a digital signal. The signal may be, for example, audio, pictures and video. If the signal is copied, then the information is also carried in the copy. In visible watermarking, the information is visible in the picture or video. Typically, the information is text or a logo which identifies the owner of the media. Digital watermarking is distinct from additional file information called metadata, in that the data is carried in the signal itself, not in addition to the signal.
Watermarking allows a producer to permanently indicate the ownership or source of a media, but it does not prevent others from redistributing the files. Watermarks, also, are permanent and are displayed even when shown in a format for which the media was intended, for example, on the website of the media owner. This permanency degrades the viewing experience to a user.